All-Inside Posterior Cruciate Ligament Reconstruction Using Autologous Quadriceps Tendon–Bone Block

Posterior cruciate ligament ruptures account for nearly 20% of knee ligament lesions. These may be either isolated or occur as part of multiligament injuries. In most of the cases, conservative treatment is recommended, but when operative treatment is required, this is technically demanding. Several posterior cruciate ligament reconstructive techniques have been described, but some concerns still remain regarding graft choice, tunnels position, visualization of the posterior compartment and graft fixation. We describe an arthroscopic all-inside technique using a single-bundle autologous quadriceps tendon with patellar bone block.

T he posterior cruciate ligament (PCL) is composed of 2 main bundles: anterolateral and posteromedial.The native ligament is extremely stiff, averaging 38 mm in length and 13 mm in diameter, and it is the primary restraint to posterior tibial translation.
Posterior cruciate ligament reconstruction (PCLR) procedures are challenging surgeries.Numerous reconstructive techniques have been described to treat PCL deficiency, including both single-and doublebundle reconstructions using open inlay or arthroscopic techniques.
Some evidence suggests that the use of autograft may reduce posterior laxity compared with allograft tendon; however, one of the main concerns is to obtain a thickness good enough to replace the native PCL. 1,2n this paper, we describe an anatomic, single-bundle, all-inside approach for arthroscopic PCLR using autologous quadriceps tendonebone graft.

Surgical Technique (With Video Illustration)
General Preparation After regional anesthesia, the patient is placed in the supine position; antibiotic prophylaxis is administered.A tourniquet is applied on the operative thigh and the knee is checked for full range of motion and confirmed to be stable on the foot roll at 90 of flexion.

Surgical Approach
A first, diagnostic arthroscopy is performed through standard anterolateral (AL) and anteromedial (AM) portals using a 30 arthroscope, in order to check for any associated intra-articular pathology.The femoral remnant of the anterolateral PCL bundle is dissected and the footprint is exposed, with care taken to maintain the meniscofemoral ligament untouched (Video 1).The posteromedial portal (PM) is then performed to clear the tibial PCL footprint, avoiding damaging the shiny white fibers of the posterior root of the medial meniscus (Fig 1).

Graft Harvest
With the leg flexed at 90 , a longitudinal 5-cm incision is made from the edge of the proximal pole of the patella, at its midpoint extending proximally.Subcutaneous fat and paratenon directly over the quadriceps tendon (QT) are excised.The QT and vastus medialis oblique muscle are identified.Manipulation of the retractors and the use of the arthroscope under the subcutaneous tissue allow for adequate visualization of the proximal QT.We obtain a 10 mm-wide graft from the  1).A thin fat layer exists deep to the tendon and superficial to the capsule, which should alert the surgeon to avoid deeper dissection or the risk of capsular violation.The patella is marked and a 1-cmwide and 2-cm-long bone block is harvested using an oscillating saw (Video 1).
Any capsular rents must be firmly closed and its integrity can be assessed by filling the joint with the arthroscopic fluid and examining for any leaks.The QT and its paratenon are sutured using absorbable wire and a sponge is placed under the incision delaying the subcutaneous and cutaneous suture at the end of the procedure.

Graft Preparation
The graft is prepared in the back table according to the GraftLink principles. 3The FiberTag Tightrope device (Arthrex, Naples, FL) is linked to the free end of the graft.A single hole is made at the center of the bone block using a 1.2-mm drill bit.An 0.8-mm metal wire is passed through the aforementioned hole, making a loop around the bone.The boneetendon passage is marked with the marking pen and the graft diameter is then confirmed (Fig 3).

Tunnel Preparation
The PCL tibial guide (Arthrex) is settled at 70 and it is inserted through the AM portal pointing to the tibial PCL footprint.A K-wire is introduced and proper position is checked under fluoroscopy control.The pin sleeve is then tapped into the tibia, the K-    A 2.4-mm K-wire is pointed into the anterolateral PCL bundle through AL portal.For a better positioning, a cannulated drill is used as a guide.Then, a 30-mm femoral socket is drilled using progressive burrs until reaching a diameter 1 mm greater than the bone block.A suture shuttle is passed into the femoral tunnel and dragged through the PM portal.At this point, both femoral ant tibial suture shuttle are retrieved through the AM portal in order to avoid soft-tissue interposition between them.

Graft Passage and Fixation
The femoral suture shuttle is pulled out as first in order to sit the patellar bone block into the femoral socket.The fixation is obtained by a 9Â30 mm metal screw introduced through the AL portal.The screw is positioned against the posterior wall of the tunnel in order to push the graft anteriorly and restore the anatomical PCL insertion.Afterward, the tendinous extremity of the graft is pulled from the AM portal into the tibial socket.A metal trocar is introduced  through the PM portal in order to obtain a pulley effect that minimize the "killer turn" effect (Video 1). 4 The tibial fixation is reached by tightening the FiberTag device over a 14-mm round SutureButton (Arthrex).The knee is then moved through a cyclic range of motion multiple times and the tensioning of the FiberTag device is performed again, keeping the knee in a reduced position at 90 of flexion (Fig 5 and Table 2).

End of the Procedure
At the end of the procedure, a last arthroscopic check is performed to ensure the correct tension of the graft.Torniquet is removed and meticulous hemostasis is performed.Wounds are irrigated and sutured.Elastic stocking is used in order to minimize knee and leg swelling.Final radiographs are performed (Fig 6).

Postoperative Rehabilitation
A knee brace with proximal tibial support is applied for 30 days' postoperatively.The patient is allowed to perform partial weight-bearing for the first month, and full weight-bearing is allowed after 30 days' postoperatively.Quadriceps isometric exercise, straight-leg raising exercise, and passive range of motion should be initiated as early as possible.

Discussion
PCLR is a technically demanding surgery, and many reconstructive techniques have been described.However, there are some concerns regarding the graft choice and the best surgical technique.No significant clinical differences have been shown between graft types used for PCLR, even though some evidence suggests that the use of autograft may result in reduced posterior laxity relative to allograft. 3The autogenous QT-B offers superior size and strength compared with other autografts, as the bone plug provides additional length and it allows accelerated bone-to-bone healing.The all-inside technique allows the creation of half tunnels both in the femur and in the tibia, preserving bone stock, minimizing the risk of tunnel widening and tunnel convergence in case of multiligamentous knee reconstruction.Moreover, the creation of sockets instead of full tunnels minimizes the "windshield effect," and the all-inside technique allows the surgeon to reduce the "killer turn" encountered in the transtibial technique, which has been associated with graft failure (Table 3). 5inally, the use of interference screws in the bony end of the graft lower the risk of tunnel enlargement as a stiffer fixation system has been used. 6The presented technique offers the advantages of boneebone healing combined with an all-inside technique.However, the technique we described is not without limitations: compared with allograft, a proper graft diameter and length may be difficult to obtain with autogenous grafts (Table 3). 2 Also, harvesting the QT-B could cause donor-site morbidity, risk of patellar fractures, and increased operative time (Table 1).

Fig 1 .Fig 2 .
Fig 1.On external medial point of view the posteromedial arthroscopic portal (PM, green cross) is shown in the preoperative setting, in a left knee, flexed at 90 .The SN (yellow line) can be visualized on translucency with the help of an arthroscope.(JL, joint line; MC, medial condyle; SM, semimembranous tibial insertion; SN, saphenous nerve.)

Fig 3 .
Fig 3.Quad tendonepatellar bone block harvested and its dimension: a 1.2-mm hole is performed at the center of the bone block, 0.8 mm metal wire carrier is passed through the hole.Boneetendon border is marked with a pencil.The FiberTag Tightrope device (Arthrex, Naples, FL) is linked to the free tendon end of the graft.

Fig 4 .
Fig 4. Intraoperative radiograph check for tibial PCL guide.It is highly recommended to ensure anatomical PCL insertion, and, to avoid potential vascular injuries, at this stage intraoperative radiograph should be mandatory.In the radiograph, the PCL tibial guide (white *) is aiming at the tibial PCL footprint, the FlipCutter (white arrow) is inserted through the tibia tunnel.(PCL, posterior cruciate ligament.)

Fig 5 .
Fig 5. PCL graft fixation scheme.(A) Intermediate step of graft insertion: retrieved from the femur tunnel the graft is passed through AM portal it is fixed on the femur at its bony end with interference screw, the other extremity of the graft is still outside of the articulation and it lies though the AM portal.The graft is then retrieved from the tibial tunnel, during the passage the trocar is inserted through the PM portal and it is positioned on the posterior border of the tibial plateau to avoid any damage to the graft in this phase, the graft is fixed in the tibia with a suture button.(B) The final results in anterior view of QT graft fixation, with graft and tunnel measures.(C) Posteromedial view of final QT graft fixation.(AM, anteromedial; PCL, posterior cruciate ligament; PM, posteromedial; QT, quadriceps tendon.)

Fig 6 .
Fig 6.Postoperative radiograph; knee brace was already fitted.The radiograph shows no intra-articular exposition of the fixation device.(A) Anteroposterior view, (B) Lateral view.

Table 1 .
Pearls and Pitfalls of the Presented Technical note Maintain the tibia at 90 of flexion in a reduced position during tibial fixationTo avoid the "killer turn," use a metal trocar through the PM portal during the graft passage into the tibial socket to obtain a pulley effect AL, anterolateral; AM, anteromedial; PCL, posterior cruciate ligament; PM, posteromedial; QT, quadriceps tendon; VMO, vastus medialis oblique.

Table 2 .
Ten Key Points for a Correct Procedure 1. AM and AL portals to check for intra-articular injuries.Perform PM portal 2. Prepare PCL tibial and femoral footprints a. Femoral footprint: preserve meniscofemoral ligament b.Tibial footprint: preserve medial meniscal posterior root (look at the shiny white fibers) 3. Harvest 7-cm QT graft and 2-cm bony block, avoiding VMO muscle fibers 4. Arm FiberTag to the free end of the graft; metal wire through the bony block 5. Retrodrill 10-mm wide and 40-mm length tibial socket 6. Perform 11-mm wide and 25-mm length femoral socket through AL portal 7. Bone block introduced through AM portal into the femoral tunnel 8. Femoral fixation with interference screw through AL portal 9. Tibial graft passage through AM portal, cortical fixation tensioning FiberTag device and 14-mm suture button 10.Cycling, retensioning and final arthroscopic examination AL, anterolateral; AM, anteromedial; PCL, posterior cruciate ligament; PM, posterolateral; QT, quadriceps tendon; VMO, vastus medialis oblique.